E.g.f.: Sum_{n>=1} x^(n^2) * exp(3*x^n) / n!.

Terms

a(0) =1a(1) =6a(2) =27a(3) =120a(4) =405a(5) =2538a(6) =5103a(7) =108216a(8) =119529a(9) =8361630a(10) =649539a(11) =1049941764a(12) =6908733a(13) =88290340362a(14) =980827520535a(16) =731794257a(18) =7360989291a(22) =721764371007